This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Children's productive vocabularies suggest that object labels (nouns) are easier to learn than action labels (verbs). Are verbs also more difficult to comprehend? Study 1 examines children's comprehension of nouns vs verbs at 14, 16, and 18 mos using a vocabulary checklist completed by parents and the preferential looking task (PLT). For the PLT, 32 children at each age are randomly assigned to the noun vs. verb condition. Children view two objects or actions before (baseline) and after (test) one of the objects or actions is labeled. Comprehension is defined as an increase in looking at the labeled image during the test trial. We predict that at each age (1) children will comprehend verbs and nouns, and (2) parent report will more accurately reflect children's comprehension of nouns than verbs. Study 2 examines children's ability to learn a new verb at 14, 16, and 18 mos. Children are shown a novel action that is labeled with a novel verb;a second action is presented but not labeled. 32 children at each age are randomly assigned to hear 3 vs. 7 repetitions of the novel verb. The PLT is used to assess comprehension of the novel verb. We predict: (1) at each age, children will comprehend the novel verb, (2) at 14 and 16 mos, comprehension will be successful at 7 but not 3 repetitions, and (3) at 18 mos, comprehension will be successful at both 3 and 7 repetitions.